title: Hydrocephalus in unruptured brain arteriovenous malformations: pathomechanical considerations, therapeutic implications, and clinical course.
abstract: OBJECTIVE
  The goal in this study was to present possible pathological mechanisms, clinical and imaging findings, and to describe the management and outcome in patients with hydrocephalus due to unruptured pial brain arteriovenous malformations (AVMs).
  
  
  METHODS
  Medical records and imaging findings in 8 consecutive patients with hydrocephalus caused by AVMs and treated between June 2000 and September 2007 were retrospectively reviewed to determine clinical symptoms, AVM location, venous drainage, level/cause of obstruction, and degree of hydrocephalus. Management of hydrocephalus, AVM treatment, complications, and follow-up results were evaluated.
  
  
  RESULTS
  Headaches were the most common clinical symptom (7 of 8 patients). Deep venous drainage was identified in all patients. Mechanical obstruction by the draining vein or the AVM nidus was seen in 6 patients, in whom obstruction occurred at the interventricular foramen (2 patients) or the aqueduct (4 patients). Hydrodynamic disorders following venous outflow obstruction and venous congestion of the posterior fossa led to hydrocephalus in the remaining 2 patients. Ventriculoperitoneal (VP) shunts were placed in 6 of 8 patients with a moderate to severe degree of hydrocephalus. Regression of hydrocephalus was noted in 4 patients, whereas in 2 the imaging findings were stable, 1 of whom had decreased hydrocephalus only after AVM size reduction. In 2 patients with mild hydrocephalus who were not treated with shunt insertion, 1 improved and 1 was clinically stable after AVM treatment.
  
  
  CONCLUSIONS
  The most common cause of hydrocephalus in unruptured brain AVMs is mechanical obstruction by the draining vein if it is located in a strategic position. Management should be aimed at treatment of the AVM; however, VP shunts may be necessary in acute and severe cases of hydrocephalus.
authors.affiliation: Department of Radiology, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Sasikhan
authors.initials: S
authors.lastname: Geibprasert
authors.forename: Vitor
authors.initials: V
authors.lastname: Pereira
authors.forename: Timo
authors.initials: T
authors.lastname: Krings
authors.forename: Pakorn
authors.initials: P
authors.lastname: Jiarakongmun
authors.forename: Pierre
authors.initials: P
authors.lastname: Lasjaunias
authors.forename: Sirintara
authors.initials: S
authors.lastname: Pongpech
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000209:etiology* / Q000503:physiopathology / Q000601:surgery; D002538:Intracranial Arteriovenous Malformations / Q000150:complications*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D017287:Ventriculoperitoneal Shunt